|field effect transistor |
A type of transistor, usually made of semiconductors, in which the flow of current from a source on one side to a drain on the other is regulated by the strength of an electric field. This field is produced by a voltage at a third point called the gate, which effectively squeezes or opens the channel to the flow of current. Field effect transistors are especially useful for amplifying or switching very low power signals, as found in portable wireless technology, microprocessors, and digital memory circuits. Compare bipolar transistor.
(FET) A transistor with a region of donor material with two terminals called the "source" and the "drain", and an adjoining region of acceptor material between, called the "gate". The voltage between the gate and the substrate controls the current flow between source and drain by depleting the donor region of its charge carriers to greater or lesser extent.
There are two kinds of FET's, Junction FETs and MOSFETs.
Because no current (except a minute leakage current) flows through the gate, FETs can be used to make circuits with very low power consumption.
Contrast bipolar transistor.